Pocket type air filters for use in industrial, commercial and institutional ventilation air ducts typically have a frame that holds one or more synthetic or natural fibre bags. The frame and bags are oriented in the duct with the openings of the bags open towards the flow of air with the remainder of the bags extending downstream to provide a large surface area filter for use in removing particulates from the air.
In some previous designs, several bags are provided, with each secured to a header, the headers being themselves secured within the frame. The bag material may be glued, riveted, heat sealed, ultrasonically sealed, stapled or the like to the header in a more or less permanent manner.
With these previous designs, there are often numerous components, making construction, maintenance and disposal difficult. Also, with permanent bonding of the bag material to the header, when the bag material is replaced, the header must be replaced as well, thus creating a disposal problem. The present invention is directed towards overcoming these problems.
The invention therefore provides in one aspect a single frame enclosing a plurality of parallel header plates each having complementary projections and grooves on opposite edges, the complementary projections of one header fitting into the grooves of an adjacent header and securing pocket type air filter medium between them. The air filter therefore includes three primary components: frame, header plates and filter medium, therefore allowing ease of assembly, disassembly and disposal, while creating a rigid and secure air filter.
This and other aspects of the invention are described in more detail in the description and claims that follow.